Living World Of Animals - Diversity In Living Organism - Kingdom Animalia Class 9th Science Tamilnadu Board Solution

Class 9th Science Tamilnadu Board Solution
Multiple Choice Questions
  1. Which is not an insect?A. House fly B. Bedbug C. Mosquito D. Spider…
  2. Which is not an insect?
  3. Find the group having only marine membersA. Mollusca B. Porifera C. Coelenterata D.…
  4. Mesoglea is present inA. Porifera B. Coelenterata C. Annelida D. Arthropoda…
  5. Dysentery is caused byA. Entamoeba B. Euglena C. Plasmodium D. Paramecium…
  6. Which one of the following pairs is not a poikilothermic animalA. Fishes and Amphibians B.…
  7. Identify the animal having four chambered heartA. Lizard B. Snake C. Crocodile D. Calotes…
  8. Which is not a feature of chordatesA. Green glands B. Sweat glands C. Sebaceous gland D.…
  9. The bilaterally symmetrical larvae which transform into radially symmetrical adult isA.…
  10. The animal without skull isA. Acrania B. Acephalia C. Apteria D. Acoelomate…
  11. Choose the correct terms related for HemichordateA. Vermiform, unsegmented, triploblastic,…
  12. Hermaphrodite organisms areA. Hydra, Tape worm, Earthworm, Amphioxus B. Hydra, Tape worm,…
  13. Poikilothermic organisms areA. Fish, Frog, lizard, man B. Fish, Frog, lizard, cow C. Fish,…
  14. Crop, gizzard and air sacs are seen inA. Fish B. Frog C. Bird D. Bat…
  15. Excretory organ of tape worm isA. Flame cells B. Nephridia C. Body surface D. Solenocytes…
  16. Tube like alimentary canal is found inA. Hydra B. Earth worm C. Starfish D. Ascaris…
  17. During ecdysis which of the following is shed offA. Chitin B. Mantle C. Scales D.…
  18. Cephalization is related toA. Head formation B. Gut formation C. Coelom formation D. Gonad…
Fill In The Blanks
  1. The excretory opening of Porifera is __________.
  2. The second largest phylum of animal kingdom is _________
  3. In India National deworming day is observed on _________
  4. Myotomes are seen in _________
  5. The larvae of an amphibian is _________
  6. In birds the air sacs communicate with __________
  7. Placenta is the unique characteristic feature of ___________
  8. The binomial name of our National Bird is __________
  9. Blue revolution is the rearing of __________
  10. In mammals testis are enclosed by _________
True Or False
  1. Canal system is seen in coelenterates.
  2. Hermaphrodite animals have both male and female sex organs.
  3. Nephridia are the respiratory organ of Annelida.
  4. Bipinnaria is the larva of Mollusca.
  5. Balanoglossus is a ciliary feeder.
  6. Fishes have two chambered heart.
  7. Skin of reptilians are smooth and moist
  8. Wings of birds are the modified forelimbs
  9. Female mammals have scrotal sacs
  10. Cloaca is present in all vertebrates.
Match The Following
  1. Match the following:
Assertion And Reason Type
  1. Assertion: The hydra is a diploblastic organism Reason: They have two germ layersA.…
  2. Assertion :The prochordate are grouped under Acrania Reason: They have well defined…
Very Short Answer Type
  1. Define taxonomy?
  2. What is a nematocyst?
  3. Why coelenterates are called diploblastic animals?
  4. Which organism is called as Friend of farmers? Why?
  5. List the respiratory organs of amphibians.
  6. Differentiate between tube feet and false feet.
  7. Are Jelly fish and star fish similar to catfish? Give reasons
  8. What is acrania?
  9. What are the sub-phylum of prochordates?
  10. Why are frogs said to be amphibians?
  11. What is silver revolution?
Short Answer Type
  1. Give an account on phylum Annelida.
  2. List the excretory organs of invertebrates in relation to their habitats.…
  3. How is the body wall of coelenterates arranged?
  4. Differentiate between flat worms and round worms?
  5. Outline the flow charts of Phylum Chordata
  6. List five characteristic features of fishes.
  7. Comment on the aquatic and terrestrial habits of amphibians
  8. How is the reproductive characters of mammals different from those of Aves…
  9. On the basis of Position of notochord, classify the different Prochordates. Justify your…
  10. How are the limbs of the birds adapted for avian life?
  11. List the integumentary glands of mammals
Long Answer Type
  1. Describe the characteristic features of different Prochordates with suitable diagrams.…
  2. Outline the flow chart of invertebrate phyla
  3. List the excretory organs of invertebrates in relation with the animals.…
  4. Give an account on phylum Arthropoda.
Flow Chart
  1. Find the missing group
  2. Find the missing group
  3. Find the correct sequence (a) Frog → Fish → Snake → Dove → Lion (b) Fish → Snake → Frog →…
  4. Visit to the near by garden of your school and give the answers for the following…
  5. Visit to a pond ecosystem and collect the names of animals observed. Give answer for the…

Multiple Choice Questions
Question 1.

Which is not an insect?
A. House fly

B. Bedbug

C. Mosquito

D. Spider


Answer:

Spider is not an insect. It is a small animal that belongs to the phylum Anthropoda (organism with jointed legs). Housefly, bedbug and mosquito are insects.


Question 2.

Which is not an insect?
A. House fly

B. Bedbug

C. Mosquito

D. Spider


Answer:

Spider is not an insect. It is a small animal that belongs to the phylum Anthropoda (organism with jointed legs). Housefly, bedbug and mosquito are insects.


Question 3.

Find the group having only marine members
A. Mollusca

B. Porifera

C. Coelenterata

D. Echinodermata


Answer:

The “Echiondermata” group consists only marine organisms. The phylum Echinodermata means spiny skinned animals. For example: Star fish, Sea Lily, Sea Urchin etc


Question 4.

Mesoglea is present in
A. Porifera

B. Coelenterata

C. Annelida

D. Arthropoda


Answer:

All coelenterates are aquatic animals.

i. The body of such animals is radial.


ii. The body wall has two layers of cells.


iii. The two layers of cells are separated by a jelly-like substance called Mesoglea.


Question 5.

Dysentery is caused by
A. Entamoeba

B. Euglena

C. Plasmodium

D. Paramecium


Answer:

Amoebic dysentery is caused by a protozoa called

“Entamoeba histolytica”. This is mostly found in dirty food and water.


Note: Protozoa means “proto”- first; “zoa” – animals. This phylum includes a great diversity of small, microscopic organisms.


Question 6.

Which one of the following pairs is not a poikilothermic animal
A. Fishes and Amphibians

B. Amphibians and Aves

C. Aves and Mammals

D. Reptiles and mammals


Answer:

Poikilothermic animals are referred as cold-blood animals. The temperature of their body changes with the temperature of surroundings.

i. Fishes, amphibians and reptiles are cold-blood animals. Hence they are poikilothermic animals.


ii. Aves and mammals are warm-blood animals. Hence this pair is not a poikilothermic animal.


Question 7.

Identify the animal having four chambered heart
A. Lizard

B. Snake

C. Crocodile

D. Calotes


Answer:

All the reptiles have three-chambered heart. But crocodile (an exception) has four-chambered heart. The reptiles having three-membered heart are lizard, snake, calote (a category of lizard), frog, toad etc.


Question 8.

Which is not a feature of chordates
A. Green glands

B. Sweat glands

C. Sebaceous gland

D. Mammary gland


Answer:

Chordates have four different glands which are:

i. Sweat glands


ii. Sebaceous glands


iii. Scent glands


iv. Mammary glands


Hence, green gland is not a feature of chordates.


Note: The phylum “Arthropoda” have green glands. The word arthropod means jointed legs.


Question 9.

The bilaterally symmetrical larvae which transform into radially symmetrical adult is
A. Bipinnaria

B. Trochophore

C. Tadpole

D. Polyp


Answer:

The most common larva is a bipinnaria larva which is bilateral symmetrical and when it becomes adult, it transforms itself into radially symmetrical.

Note: In radial symmetry:


i. The body parts are arranged around the central axis.


ii. If we cut through the central axis in any direction, it can be divided into similar halves.


iii. E.g. Hydra, jelly fish and star fish.


In bilateral symmetry:


i. The body parts are arranged along a central axis.


ii. If we cut through the central axis, we get two identical halves.


iii. E.g. Frog.



Question 10.

The animal without skull is
A. Acrania

B. Acephalia

C. Apteria

D. Acoelomate


Answer:

Acrania is an animal that is not having a skull (cranium). Hence it is considered as Sub-phylum Acraniata – Prochordata.


Question 11.

Choose the correct terms related for Hemichordate
A. Vermiform, unsegmented, triploblastic, ciliary feeders

B. Vermiform, segmented, triploblastic, ciliary feeders

C. Vermiform, unsegmented, diploblastic, ciliary feeders

D. Vermiform, unsegmented, triploblastic, filter feeders


Answer:

In Hemichordates:

i. Marine organisms do not have backbone.


ii. The body is soft and vermiform (body like worm)


iii. The body is unsegmented (no segments are there)


iv. The body is tribloplastic (three germ layers).


v. They act as filter feeders.


Question 12.

Hermaphrodite organisms are
A. Hydra, Tape worm, Earthworm, Amphioxus

B. Hydra, Tape worm, Earthworm, Ascidian

C. Hydra, Tape worm, Earthworm, Balanoglossus

D. Hydra, Tape worm, Ascaris, Earthworm


Answer:

Hermaphrodite organisms include worms. These worms have both female and male reproductive organs. Thus, Hydra, Tapeworm, Ascaris (round worm), Earthworm are hermaphrodite organisms.


Question 13.

Poikilothermic organisms are
A. Fish, Frog, lizard, man

B. Fish, Frog, lizard, cow

C. Fish, Frog, lizard, snake

D. Fish, Frog, lizard, crow


Answer:

Poikilothermic organisms are referred as cold-blood animals.

i. Fishes, amphibians and reptiles are cold-blood animals. Hence fish, frog, lizard, snake are poikilothermic organisms.


ii. Aves (birds) and mammals are warm-blood animals. Hence crow (ave), man and cow (mammals) are not poikilothermic organisms.


Question 14.

Crop, gizzard and air sacs are seen in
A. Fish

B. Frog

C. Bird

D. Bat


Answer:

Crop, gizzard and air sacs are seen in a bird.

i. Alimentary canal is provided with crop and gizzard.


ii. Air sacs are present to make the bird light weight.



Question 15.

Excretory organ of tape worm is
A. Flame cells

B. Nephridia

C. Body surface

D. Solenocytes


Answer:

In tape worm, excretion takes place through flame cells.

i. Tapeworms come under the category of phylum “Platyhelminthes”.


ii. This phylum includes all the flatworms.


Question 16.

Tube like alimentary canal is found in
A. Hydra

B. Earth worm

C. Starfish

D. Ascaris


Answer:

The alimentary canal in a round worm is a straight tube. Ascaris is an example of round worm.


Question 17.

During ecdysis which of the following is shed off
A. Chitin

B. Mantle

C. Scales

D. Operculum


Answer:

During ecdysis (shedding old skin) or moulting, the animal has to shed off “chitin” periodically. In Arthroprod, the exoskeleton is made up of chitin.


Question 18.

Cephalization is related to
A. Head formation

B. Gut formation

C. Coelom formation

D. Gonad formation


Answer:

Cephalization is a process of head formation.



Fill In The Blanks
Question 1.

The excretory opening of Porifera is __________.


Answer:

Osculum

The excretory opening of Porifera is osculum. Osculum helps in the circulation of water and excretes out its waste.




Question 2.

The second largest phylum of animal kingdom is _________


Answer:

Phylum Mollusca (Soft Bodied Animals)

Phylum Mollusca:


i. It is the second largest phylum of animal kingdom.


ii. It is a very successful and diverse group of aquatic animals living in both marine and freshwater habitats.


iii. These are soft-blooded animals.


iv. Their body is unsegmented.


v. For example: Octopus, Giant squid



Question 3.

In India National deworming day is observed on _________


Answer:

10th February

National Deworming day is observed on February 10th every year in India.


i. Deworming is a treatment for Ascaris infection.


ii. Ascaris causes infection in the human intestine.


iii. This can cause stomach pain and many diseases.



Question 4.

Myotomes are seen in _________


Answer:

Fishes

In fishes:


i. The body of fish has a covering of scales.


ii. Body muscles are arranged into segments called myotomes.


iii. The gills help in respiration.



Question 5.

The larvae of an amphibian is _________


Answer:

tadpole

The larvae of an amphibian is tadpole. Amphibians can live in both land and water. They have three-chambered heart.



Tadpole-Larva of frog



Question 6.

In birds the air sacs communicate with __________


Answer:

Air space

Air sacs are present to make the bird light weight. So that they can easily communicate with the air. The bones are filled with air hence called pneumatic bones.



Question 7.

Placenta is the unique characteristic feature of ___________


Answer:

mammals

Placenta is a characteristic feature of mammals. Placenta helps in the exchange of rich nutrients between mother and child in the womb.



Question 8.

The binomial name of our National Bird is __________


Answer:

Pavo cristatus

Our national bird is Peacock. Its binomial name is Pavo cristatus.


i. Carolus Linnaeus introduced the method of naming the animals with two names known as binomial names.


ii. The first name is called genus which is always written with the first letter capital.


iii. The second one is the species name always written in small letter.



Question 9.

Blue revolution is the rearing of __________


Answer:

Fish and prawn production

The blue revolution is the rearing of fish and prawn production. Blue revolution is mainly for aquaculture.


Note: Culturing of aquatic organisms is referred to as Aquaculture.



Question 10.

In mammals testis are enclosed by _________


Answer:

Scrotal sacs

In mammals:


i. Testis lie outside the body cavity.


ii. These are enclosed in scrotal sacs.


iii. Fertilization is always internal.




True Or False
Question 1.

Canal system is seen in coelenterates.


Answer:

False

The canal system is absent in coelenterates. The symmetery of coelenterates is radial. The canal system is mainly observed in Porifera.



Question 2.

Hermaphrodite animals have both male and female sex organs.


Answer:

True

Hermaphrodite animals have both female and male reproductive organs in a single individual.


i. These members are parasitic in nature.


ii. These include flatworms (example-tapeworm)



Question 3.

Nephridia are the respiratory organ of Annelida.


Answer:

False

Nephridia is not a respiratory organ of Annelida.


i. Nephridia is an excretory organ of Annelida.


ii. It helps to remove metabolic wastes from animal’s body .



Question 4.

Bipinnaria is the larva of Mollusca.


Answer:

False

Bipinnaria is the larva of Echinodermata which are spiny skinned animals. Trochophore, and veliger larva are the most common larvae of


Mollusca (soft bodied animals).



Question 5.

Balanoglossus is a ciliary feeder.


Answer:

False

Balanoglossus is a hermaphrodite animal. Hermaphrodite animals are filter feeder. They are not ciliary feeder.



Question 6.

Fishes have two chambered heart.


Answer:

True

Fishes have two chambered heart with an auricle and a ventricle. These are poikilothermic animals. This means fishes are cold blooded organisms.



Note: Ventricle pumps blood out of the heart. Atrium receives blood returning to the heart.



Question 7.

Skin of reptilians are smooth and moist


Answer:

False

Skin of amphibians (can live in both land and water) are smooth and moist whereas skin of reptiles is dry. Basically skin glands are absent in reptilians.



Question 8.

Wings of birds are the modified forelimbs


Answer:

True

Birds have two pairs of limbs, in that forelimbs are modified wings. The hind limbs are for walking and running.



Question 9.

Female mammals have scrotal sacs


Answer:

False

Male mammals have scrotal sacs. Testis (a part of male reproductive organ) lie outside the body cavity, enclosed in scrotal sacs.



Question 10.

Cloaca is present in all vertebrates.


Answer:

False

Cloaca is not present in all vertebrates. It is present in amphibians, reptiles, birds, fishes (such as sharks). It is absent in mammals and fishes having bones.




Match The Following
Question 1.

Match the following:



Answer:

(A)- iv


In phylum “Coelenterata”, organism may exist only in two different body forms namely a “polyp” and a “medusa”.


Hydra is an example of polyp.



Hydra - a polyp


(B)- iii


The phylum “Platyhelminthes” includes flat worms.


Tapeworm is a type of flatworm. The binomial name of tapeworm is


“Taenia solium”.


(C)- ii


The phylum “Echinodermata” which consists only marine animals. These are spiny-skinned animals. Star fish belongs to this phylum. Some other animals are sea urchin, sea lily etc.



Starfish- Echinodermata


(D) – i


Mollusca is the second largest phylum of animal kingdom.


i. These are soft bodied animals without segmentation.


ii. The body is covered by an outer shell.


iii. Example: snail



Snail – Mollusca




Assertion And Reason Type
Question 1.

Assertion: The hydra is a diploblastic organism

Reason: They have two germ layers
A. Assertion is correct and the reason is wrong

B. Reason is correct and the Assertion is wrong

C. Both assertion and reason is correct

D. Both assertion and reason is wrong


Answer:

Hydra belongs to the phylum of Porifera.


i. In Porifera, the body wall has two layers of cells.


ii. Due to presence of two layers , they are said to be diploblastic


Animals.


Hence, both assertion and reason is correct.


Question 2.

Assertion :The prochordate are grouped under Acrania

Reason: They have well defined cranium
A. Assertion is correct and the reason is wrong

B. Reason is correct and the assertion is wrong

C. Both assertion and reason is correct

D. Both assertion and reason is wrong


Answer:

The Prochordates are considered as the development Of vertebrata. Since they do not have a cranium or skull they are referred to as Acrania.


Hence, assertion is correct and the reason is wrong.



Very Short Answer Type
Question 1.

Define taxonomy?


Answer:

Taxonomy is the theoretical study of classification of organisms including its basic principles, procedures and rules. Classification is based on:

i. Similarities of organisms.


ii. Dissimilarities of organisms.


iii. Relationship between organisms



Question 2.

What is a nematocyst?


Answer:

In phylum Porifera, the tentacles bear stinging cells are called nematocyst. Nematocysts are also called cnidoblasts.

i. Cnidocil is present in Porifera.


ii. They are also called as Cnidaria.



Question 3.

Why coelenterates are called diploblastic animals?


Answer:

Coelenterates are called diploblastic animals because:

i. Coelenterates animals have two layers of cells.


ii. One layer is ectoderm (outer) and other one is endoderm (inner)


iii. Both the layers are separated by a jelly substance called mesoglea.


iv. Due to the presence of two layers, they are called diploblastic animals.



Question 4.

Which organism is called as Friend of farmers? Why?


Answer:

Earthworm is called as Friend of farmers because:

i. They eat all the animal and plant wastes (biodegradable materials) present into the soil.


ii. As a result, they convert them into good manure.


iii. This increases soil fertility.


iv. They are eco-friendly organisms.


v. They make the soil more porous and airy by loosening the soil.


vi. They increase the water holding capacity.



Question 5.

List the respiratory organs of amphibians.


Answer:

The respiratory organs of amphibians are:

i. Gills


ii. Skin


iii. Bucco-phrynx


iv. Lungs



Question 6.

Differentiate between tube feet and false feet.


Answer:



Question 7.

Are Jelly fish and star fish similar to catfish? Give reasons


Answer:

No Jelly fish and star fish are not similar to catfish. The differences are:



Question 8.

What is acrania?


Answer:

The Prochordates are considered as the development of vertebrata. Since they do not have a cranium or skull they are referred to as Acrania.



Question 9.

What are the sub-phylum of prochordates?


Answer:

The sub-phylum of prochordates are:

i. Hemichordata – Marine organism without backbone.



Balanglossus (Hemichordate)


ii. Cephalochordata – Small fish with unpaired dorsal fin.



iii. Urochordata – The adults are mostly degenerate, and are sessile forms.



Ascidian (Urochordate)



Question 10.

Why are frogs said to be amphibians?


Answer:

Frogs are said to be amphibians because:

i. They can live in both land and water.


ii. They spend their lives in water when they are in the form of eggs.


iii. When they become tadpoles and finally frogs, they start to live on land.



Question 11.

What is silver revolution?


Answer:

Silver revolution refers to the rise in the production of eggs. It was mainly done by providing rich nutrients to hens. Medical help was also provided to hens to increase the production of eggs.




Short Answer Type
Question 1.

Give an account on phylum Annelida.


Answer:

Phylum Annelida:

i. Earthworms, leeches and marine worms belongs to this phylum.


ii. They are segmented worms.


iii. They have a body cavity called coelom.


iv. They have movable bristles called setae which help in their movement.


v. They have a nervous system with brain.


vi. They have Nephridia which help to remove metabolic wastes.


vii. The most common larva is trochopore.



Earthworms



Leech



Question 2.

List the excretory organs of invertebrates in relation to their habitats.


Answer:

The excretory organs of invertebrates in relation to their habitats are:

i. Phylum Protozoa: Excretion of waste (carbon dioxide and ammonia) takes place by the process of diffusion through body surface. There are no specific excretory organs.


ii. Phylum Porifera: Pore-bearers excrete through osculum.


iii. Phylum Plathyelminthes: Flat worms excrete through flame cells.


iv. Phylum Annelida: Nephridia are excretory structures and help to remove metabolic wastes.


v. Phylum Arthropoda: Excretion occurs through malphigian Tubules and green glands


vi. Phylum Echinoderamata: Excretory organs are absent.


vii. Phylum Coelenterata: There are no particular excretory organs. Excretion take place by the process of diffusion.


viii. Phylum Mollusca: Excretion takes place through one or two pairs of kidneys present in them.



Question 3.

How is the body wall of coelenterates arranged?


Answer:

Coelenterates:

i. The body symmetry of coelenterates is radial.


ii. The body wall is of two layers.


iii. One layer is ectoderm (outer) and other layer is endoderm (inner).


iv. Both the walls are separated by a jelly-like substance called mesoglea.


v. Due to the presence of two layers, hence they are called diploblastic animals.



Question 4.

Differentiate between flat worms and round worms?


Answer:



Question 5.

Outline the flow charts of Phylum Chordata


Answer:


Phylum chordates are the animals with backbones. This phylum derives its name from one of the common characteristics of this group namely the notochord.


i. Prochordates are considered as the development of vertebrata.


As they do not have brain, hence they are referred as Acrania.


ii. These are divided into three sub-pylums which are Hemichordata, Cephalochordata and Urochordata.


Hemichordata


i. These are marine organisms.


ii. They do not have backbones.


iii. The body is soft, bilateral symmetrical and unsegmented.


Cephalochordata


i. These are small fish.


ii. These are marine organisms with unpaired dorsal fin.


Urochordata


i. The adults are mostly degenerate, and are sessile forms.


ii. The body is enveloped by a tunic or test.



Question 6.

List five characteristic features of fishes.


Answer:

Five characteristic features of fishes are:

i. Fishes are poikilothermic (cold blooded animals)


ii. The paired and median fins help in their movement.


iii. They respire through gills


iv. They have two chambered heart.


v. The body has a covering of scales.




Question 7.

Comment on the aquatic and terrestrial habits of amphibians


Answer:

Let’s take example of frogs:

i. Frogs can live in both land and water.


ii. They spend their lives in water when they are in the form of eggs.


iii. When they become tadpoles and finally frogs, they start to live on land.


That’s how amphibians change their aquatic and terrestrial habits.



Question 8.

How is the reproductive characters of mammals different from those of Aves


Answer:

The differences are:



Question 9.

On the basis of Position of notochord, classify the different Prochordates. Justify your answer


Answer:

The three sub-phylums are classified on the basis of notochord:

i. Sub phylum Hemichordata


The notochord is persistent as the stomochord in the anterior region of the animal.


ii. Sub phylum Cephalochordata


The persistent notochord extends forward beyond the brain.


iii. Sub phylum Urochordata


In Urochordata the notochord is confined to the tail region of the larva.



Question 10.

How are the limbs of the birds adapted for avian life?


Answer:

The limbs of the birds:

i. The birds have two pairs of limbs.


ii. In that, forelimbs are modified as wings.


iii. The hind limbs are adapted for walking and running.



Question 11.

List the integumentary glands of mammals


Answer:

The four different integumentary (skin) glands of mammals are:

i. Sweat glands – These are used in cooling the skin.


ii. Sebaceous glands – These glands are associated with hair. These


secrete an oily substance called sebum itno the hair of skin.


That’s how sebum protects the skin surface.



Sebacious gland


iii. Scent glands – These glands attract other ones.


iv. Mammary glands –These glands secrete milk for the young ones.




Long Answer Type
Question 1.

Describe the characteristic features of different Prochordates with suitable diagrams.


Answer:

Prochordates:

i. Prochordates are considered as the development of vertebrata.


As they do not have brain, hence they are referred as Acrania.


ii. These are divided into three sub-pylums which are Hemichordata, Cephalochordata and Urochordata.


iii. The three sub-phylums are classified on the basis of notochord.


Hemichordata


i. These are marine organisms.


ii. They do not have backbones.


iii. The body is soft, bilateral symmetrical and unsegmented.


iv. The notochord is persistent as the stomochord in the anterior region of the animal.



Balanoglossus


Cephalochordata


i. These are small fish.


ii. These are marine organisms with unpaired dorsal fin.


iii. The persistent notochord extends forward beyond the brain.